who

0Hello,02br
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00I have to join these sentences using "who", where/that/whom /whose etc.02br
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001. The girl was injured in the accident. She is now in the hospital.02br
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00a) The girl who was injured in the accident is now in the hospital.02br
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00b) The girl ,who was injured in the accident , is now in the hospital.02br
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00Which one is correct?02br
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002. Summet has a dog. It is called Bruno.02br
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00a) Summet has a dog which is called Bruno.02br
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00b) Summet has a dog that is called Bruno.02br
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00c)Summet has a dog who is called Bruno.02br
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00Whic one is correct among (a), (b), (c)?02br
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003.) Ram is a widower. His wife has died. He has not re- married.02br
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00a) Ram is a widower whose wife has died has not re-married.02br
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00b) Ram is a widower , whose wife has died, has not re-married.02br
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00Which is correct between (a) and (b)?02br
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00I also want to know in what situation comma is needed?0-